KR101942602B1 - Conductive particles, conductive material, and connection structure - Google Patents

Abstract

The present invention provides conductive particles capable of lowering the connection resistance between electrodes. The conductive particles 1 according to the present invention include base particles 2, a conductive layer 3 covering the base particles 2, and a plurality of core materials 4 embedded in the conductive layer 3, Respectively. The conductive layer 3 has a plurality of projections 3a on its outer surface. The core material 4 is disposed inside the projections 3a of the conductive layer 3. [ The surface of the base particle 2 and the surface of the core material 4 are spaced from each other. The average distance between the surface of the base particles 2 and the surface of the core material 4 exceeds 5 nm.

Description

TECHNICAL FIELD [0001] The present invention relates to conductive particles, conductive materials, and connection structures,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to conductive particles in which conductive layers are disposed on the surface of base particles, and more particularly to conductive particles which can be used for electrical connection between electrodes, for example. The present invention also relates to a conductive material and a connection structure using the conductive particles.

Anisotropic conductive paste such as anisotropic conductive paste and anisotropic conductive film are widely known. In the anisotropic conductive material, the conductive particles are dispersed in the binder resin.

The anisotropic conductive material is used for connection between the IC chip and the flexible printed circuit board and for connection between the IC chip and the circuit board having the ITO electrode. For example, after the anisotropic conductive material is disposed between the electrodes of the IC chip and the electrodes of the circuit board, these electrodes can be electrically connected by heating and pressing.

As an example of the above conductive particles, Patent Document 1 below discloses a conductive particle in which a nickel conductive layer or a nickel alloy conductive layer is formed on the surface of spherical base particles having an average particle diameter of 1 to 20 占 퐉 by electroless plating, . The conductive particles have minute projections of 0.05 to 4 占 퐉 in the outermost layer of the conductive layer. The conductive layer and the protrusion are substantially continuously connected.

In the following Patent Document 2, there is disclosed a laminate comprising a plastic core, a polymer electrolyte layer covering the plastic core, metal particles adsorbed to the plastic core through the polymer electrolyte layer, A conductive particle having a metal plating layer is disclosed.

The following Patent Document 3 discloses a conductive particle in which a metal plating film layer containing nickel and phosphorus and a multilayered conductive layer between the gold layer are formed on the surface of base particles. In the conductive particles, a core material is disposed on the surface of the base particle, and the core material is covered with a conductive layer. The conductive layer is raised by the core material, and protrusions are formed on the surface of the conductive layer.

Japanese Patent Application Laid-Open No. 2000-243132 Japanese Patent Laid-Open Publication No. 2011-108446 Japanese Patent Application Laid-Open No. 2006-228475

The above-described Patent Documents 1 to 3 disclose conductive particles having projections on the outer surface of the conductive layer. There are many cases where an oxide film is formed on the surface of the conductive layer of the electrode and the conductive particles which are connected by the conductive particles. The protrusions of the conductive layer are formed so as to exclude the oxide film on the surfaces of the electrodes and the conductive particles when the electrodes are squeezed through the conductive particles to contact the conductive layer and the electrodes.

However, when the electrodes are connected using the conventional conductive particles having protrusions on the outer surface of the conductive layer, the oxide coating on the surfaces of the electrodes and the conductive particles can not be sufficiently removed, resulting in a high connection resistance.

An object of the present invention is to provide a conductive particle capable of lowering the connection resistance between electrodes when a connection structure is obtained by connecting the electrodes, and a conductive material and a connection structure using the conductive particles.

)되어 있는 복수의 코어 물질을 구비하고, 상기 도전층이 외측의 표면에 복수의 돌기를 갖고, 상기 도전층의 상기 돌기의 내측에 상기 코어 물질이 배치되어 있고, 상기 기재 입자와 상기 코어 물질 사이에 상기 도전층이 배치되어 있고, 상기 기재 입자의 표면과 상기 코어 물질의 표면이 거리를 두고 있고, 상기 기재 입자의 표면과 상기 코어 물질의 표면 사이의 평균 거리가 5 nm를 초과하는 도전성 입자가 제공된다.According to a broad aspect of the present invention, there is provided a semiconductor device comprising: base particles; a conductive layer covering the base particles;

Wherein the core material is disposed inside the projection of the conductive layer, and the core material is disposed between the base material particles and the core material, Wherein the surface of the base material and the surface of the core material are at a distance from each other and the average distance between the surface of the base material and the surface of the core material is greater than 5 nm, / RTI >

In a specific aspect of the conductive particles according to the present invention, the average distance between the surface of the base particle and the surface of the core material is more than 5 nm but not more than 800 nm.

In a specific aspect of the conductive particles according to the present invention, the ratio of the number of core materials having a distance between the surface of the base particle and the surface of the core material of the core material exceeding 5 nm in the total number 100% of the core material is 80% And not more than 100%.

In a specific aspect of the conductive particles according to the present invention, the metal element most contained in the core material and the metal element most contained in the conductive layer are the same.

In another specific aspect of the conductive particle according to the present invention, the conductive layer includes a first conductive layer covering the base particle, and a second conductive layer covering the first conductive layer and the core material, Wherein the core material is disposed on a surface of the first conductive layer and embedded in the second conductive layer, the second conductive layer has a plurality of projections on an outer surface thereof, The core material is disposed on the inner side of the projections, and the first conductive layer is disposed between the base particles and the core material.

In another specific aspect of the conductive particles according to the present invention, the metal element most contained in the core material and the metal element most contained in the second conductive layer are the same.

In another specific aspect of the conductive particles according to the present invention, the conductive layer is a single-layer conductive layer.

In another specific aspect of the conductive particles according to the present invention, the core material is a metal particle.

In another specific aspect of the conductive particles according to the present invention, an insulating material attached to the surface of the conductive layer is further provided.

The conductive material according to the present invention includes the above-described conductive particles and a binder resin.

The connecting structure according to the present invention includes a first connecting object member, a second connecting object member, and a connecting portion connecting the first and second connecting object members, wherein the connecting portion is formed by the above- Or formed of a conductive material containing the conductive particles and a binder resin.

The conductive particle according to the present invention comprises a base particle, a conductive layer covering the base particle, and a plurality of core materials embedded in the conductive layer, wherein the conductive layer has a projection on the outer surface, Wherein the core material is disposed inside the protrusion of the conductive layer and the conductive layer is disposed between the base material particle and the core material and the surface of the base material particle and the surface of the core material are distanced from each other , The average distance between the surface of the base particles and the surface of the core material exceeds 5 nm, so that the connection resistance between the electrodes can be reduced when the conductive particles according to the present invention are used for connection between the electrodes.

1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention.
2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention.
3 is a cross-sectional view showing a conductive particle according to a third embodiment of the present invention.
4 is a front sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

Hereinafter, the details of the present invention will be described.

The conductive particles according to the present invention comprise base particles, a conductive layer covering the base particles, and a plurality of core materials embedded in the conductive layer. The conductive layer has a plurality of projections on the outer surface. And the core material is disposed inside the protrusion of the conductive layer. And the conductive layer is disposed between the base particles and the core material. And a portion of the conductive layer is disposed between the base particles and the core material. The surface of the base particle and the surface of the core material are spaced apart. The average distance between the surface of the base particles and the surface of the core material exceeds 5 nm.

In many cases, an oxide film is formed on the surface of an electrode connected by conductive particles. In many cases, an oxide film is formed on the outer surface of the conductive layer. The conductive layer has a plurality of protrusions on the outer surface, and the conductive particles are disposed between the electrodes, and then the conductive particles are pressed, whereby the oxide film is removed by the protrusions. Therefore, the electrode and the conductive particles can be brought into contact with each other, and the connection resistance between the electrodes can be reduced.

In the conductive particle according to the present invention, the conductive layer is disposed between the base particle and the core material, and the surface of the base particle and the surface of the core material are spaced from each other, Since the average distance between the surfaces of the core material exceeds 5 nm, when the conductive particles are pressed between the electrodes, the core material is hardly press-fitted into the base particles, and a part of the core material is hardly embedded in the base particles. Particularly, even if the base particles are relatively soft resin particles, the core material is difficult to press-fit base particles, and a part of the core material is difficult to sink into base particles. Therefore, the projections of the conductive layer are strongly pressed against the electrodes at the time of pressing between the electrodes. As a result, the oxide film is effectively removed by the projections. Therefore, the electrodes and the conductive particles can be effectively brought into contact with each other, and the connection resistance between the electrodes can be effectively lowered.

Further, since the conductive particles according to the present invention are provided with the above-described constitution, it is also possible to form an appropriate indentation on the electrode when the electrodes are connected by compressing the conductive particles. The indentations formed on the electrodes are concave portions of the electrodes formed by pressing the electrodes with the conductive particles. Further, when a conductive material (anisotropic conductive material or the like) in which the conductive particles are dispersed in the binder resin is used for pressing between the electrodes, the binder resin between the conductive layer and the electrodes can be effectively removed. Even if the binder resin is effectively removed, the connection resistance between the electrodes can be reduced. In addition, in the case of using the conductive particles having the insulating material, since the insulating material between the conductive layer and the electrode can be effectively removed by the projections, the reliability of conduction between the electrodes can be effectively increased.

The average distance between the surface of the base particle and the surface of the core material is preferably not less than 5 nm and not more than 5 nm from the viewpoint of further effectively excluding the oxide film of the electrode and the surface of the conductive particle and further enhancing the conduction reliability between the electrodes Preferably 10 nm or more. The upper limit of the average distance between the surface of the base particles and the surface of the core material is not particularly limited and is appropriately determined in consideration of the thickness of the conductive layer and the like. The average distance between the surface of the base particles and the surface of the core material may be 800 nm or less, or 100 nm or less. The average distance between the surface of the base particle and the surface of the core material is preferably 30 nm or less, more preferably 20 nm or less. The average distance between the surface of the base particle and the surface of the core material may be 9/10 or less of the thickness of the conductive layer, 1/2 or less, or 1/3 or less.

From the viewpoint of further effectively excluding the oxide film on the surface of the electrode and the conductive particles and further enhancing the conduction reliability between the electrodes, it is preferable that the total amount of the core material is 100% The ratio of the number of core materials having a distance exceeding 5 nm is preferably 50% or more, more preferably 80% or more and 100% or less. In all of the core material, the distance between the surface of the base particle and the surface of the core material may exceed 5 nm.

The average distance between the surface of the base particle and the surface of the core material means the distance between the surface of the base particle and each surface of the plurality of core materials (the shortest distance between the gaps), and then the measured values are averaged . The distance between the surface of the base material particle and the surface of the core material A and the distance between the surface of the base material particle and the surface of the core material B , The distance between the surface of the base particle and the surface of the core material C, the distance between the surface of the base particle and the surface of the core material D, and the distance between the surface of the base particle and the surface of the core material E were measured Is calculated by averaging the five values. When the number of core materials is more than 10, it is preferable to measure the distance between the surface of the base particles and each surface of all the core materials. However, the distance between the surface of the base particles and each surface of arbitrarily selected 10 core materials , And calculate the average distance from the ten measured values.

The distance between the surface of the base particle and the surface of the core material can be measured accurately by photographing a plurality of cross sections of the conductive particle to obtain an image, creating a stereoscopic image from the obtained image, and using the obtained stereoscopic image. The section can be photographed using a focused ion beam-scanning electron microscope (FIBSEM) or the like. For example, a thin film segment of conductive particles is produced using a focused ion beam, and a cross section is observed with a scanning electron microscope. By repeating the operation several hundred times and performing image analysis, a three-dimensional image of the particles can be obtained.

The conductive layer has projections on the outer surface. The projections are plural. In many cases, an oxide film is formed on the surface of the conductive layer and the surface of the electrode connected by the conductive particles. By using conductive particles having protrusions on the surface of the outer side of the conductive layer, conductive particles are disposed between the electrodes and pressed, whereby the oxide film is effectively removed by the protrusions. Therefore, the electrode and the conductive layer of the conductive particle can be more reliably contacted, and the connection resistance between the electrodes can be reduced. When the conductive particles are provided with an insulating material on the surface or when the conductive particles are dispersed in the binder resin to be used as a conductive material, an insulating material or a binder resin between the conductive particles and the electrode by the projections of the conductive particles It can be effectively excluded. Therefore, the conduction reliability between the electrodes can be improved.

The average height of the plurality of projections is preferably 0.001 m or more, more preferably 0.05 m or more, preferably 0.9 m or less, and more preferably 0.2 m or less. When the average height of the projections is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

Hereinafter, the details of the conductive particles, the conductive material, and the connection structure will be described.

(Conductive particles)

1 is a cross-sectional view showing a conductive particle according to a first embodiment of the present invention.

The conductive particles 1 shown in Fig. 1 include base particles 2, a conductive layer 3, a plurality of core materials 4, and an insulating material 5. The conductive layer 3 is disposed on the surface of the base particle 2. In the conductive particles 1, a single-layer conductive layer 3 is formed. The conductive layer (3) covers the base particles (2). The conductive layer 3 has a plurality of projections 3a on its outer surface. A plurality of core materials 4 are disposed on the surface of the base particle 2 and are embedded in the conductive layer 3. The core material 4 is disposed inside the projection 3a. One core material 4 is arranged inside one projection 3a. The outer surface of the conductive layer 3 is raised by the plurality of core materials 4 and a plurality of projections 3a are formed.

The conductive layer 3 is disposed between the surface of the base particle 2 and the surface of the core material 4. [ The surface of the base particle 2 and the surface of the core material 4 are spaced from each other. The core material 4 is not in contact with the base particles 2. In the conductive particle 1, the average distance between the surface of the base particle 2 and the surface of the core material 4 exceeds 5 nm. Therefore, a portion of the conductive layer 3 (conductive layer portion 3b) of sufficient thickness is disposed between the surface of the base particle 2 and the surface of the core material 4. The distance between the surface of the base particle 2 and the surface of the core material 4 is the thickness of the conductive layer portion 3b disposed between the surface of the base particle 2 and the surface of the core material 4.

The insulating material 5 is disposed on the surface of the conductive layer 3. The insulating material 5 is insulating particles. The insulating material 5 is formed of a material having an insulating property. The conductive particles may not necessarily be provided with an insulating material. Further, the conductive particles may be an insulating material, and may include an insulating layer covering the outer surface of the conductive layer instead of the insulating particles.

Fig. 2 is a cross-sectional view of a conductive particle according to a second embodiment of the present invention.

The conductive particles 11 shown in Fig. 2 include base particles 2, a conductive layer 12, a plurality of core materials 4, and an insulating material 5. The conductive layer 12 is disposed on the surface of the base particle 2. The conductive layer 12 covers the base particles 2. The conductive layer 12 has a plurality of projections 12a on its outer surface.

In the conductive particles 11, a multilayered conductive layer 12 is formed. The conductive layer 12 has a first conductive layer 16 and a second conductive layer 17. The first conductive layer 16 is disposed on the surface of the base particle 2. The first conductive layer 16 covers the base particles 2. The first conductive layer 16 is a single layer. The first conductive layer may be multi-layered.

The core material 4 is disposed on the first conductive layer 16. The core material 4 is embedded in the conductive layer 12 and the second conductive layer 17. A first conductive layer 16 is disposed between the base particles 2 and the core material 4. The first conductive layer 16 is disposed between the base particles 2 and the core material 4 so that the surface of the base particles 2 and the surface of the core material 4 are spaced from each other. The average distance between the surface of the base particles 2 and the surface of the core material 4 exceeds 5 nm. The distance between the surface of the base particle 2 and the surface of the core material 4 in the conductive particle 11 is the distance between the surface of the base particle 2 and the surface of the core material 4, And the thickness of the first conductive layer 16 (the first conductive layer 16).

The second conductive layer 17 is formed separately from the first conductive layer 16. The second conductive layer 17 is formed on the surface of the first conductive layer 16 after the first conductive layer 16 is formed. The second conductive layer 17 is disposed on the surface of the first conductive layer 16. The second conductive layer 17 covers the core material 4 and the first conductive layer 16. The second conductive layer 17 has a plurality of projections 17a on its outer surface. The plurality of core materials 4 are embedded in the second conductive layer 17. The core material 4 is disposed inside the projection 17a. The outer surface of the second conductive layer 17 is raised by the plurality of core materials 4, and the projections 17a are formed.

3 is a cross-sectional view of a conductive particle according to a third embodiment of the present invention.

The conductive particles 21 shown in Fig. 3 include base particles 2, a conductive layer 22, a plurality of core materials 4, and an insulating material 5. The conductive layer 22 is disposed on the surface of the base particle 2. The conductive layer 22 covers the base particles 2. The conductive layer 22 has a plurality of projections 22a on its outer surface.

In the conductive particles 21, a multilayered conductive layer 22 is formed. The conductive layer 22 has a first conductive layer 26, a second conductive layer 27, and a third conductive layer 28. The first conductive layer 26 is disposed on the surface of the base particle 2. The first conductive layer 26 covers the base particles 2.

The core material 4 is disposed on the first conductive layer 26. The core material 4 is embedded in the conductive layer 22 and in the second conductive layer 27. A first conductive layer 26 is disposed between the base particles 2 and the core material 4. The first conductive layer 26 is disposed between the base particles 2 and the core material 4 so that the surface of the base particles 2 and the surface of the core material 4 are spaced from each other. The average distance between the surface of the base particles 2 and the surface of the core material 4 exceeds 5 nm. The distance between the surface of the base particles 2 and the surface of the core material 4 in the conductive particles 21 is the distance between the surface of the base particles 2 and the surface of the core material 4, And the thickness of the first conductive layer 26 portion.

The second conductive layer 27 is disposed on the surface of the first conductive layer 26. The second conductive layer 27 covers the core material 4 and the first conductive layer 26. The second conductive layer 27 has a plurality of projections 27a on its outer surface. The core material 4 is disposed inside the projection 27a. The outer surface of the second conductive layer 27 is raised by the plurality of core materials 4 and the projections 27a are formed.

The third conductive layer 28 is disposed on the surface of the second conductive layer 27. The third conductive layer 28 covers the second conductive layer 27. The third conductive layer 28 has a plurality of projections 28a on its outer surface. The core material 4 is disposed inside the projection 28a. The outer surface of the third conductive layer 28 is ridged by the plurality of core materials 4, and the projections 28a are formed.

It is preferable that the metal element contained most in the core material and the metal element contained most in the conductive layer are the same. In this case, the adhesion between the core material and the conductive layer becomes good, and as a result, the connection resistance in the connection structure is further improved. In addition, the metal element most contained in the core material and the metal element most contained in the conductive layer may have a concentration gradient in the core material, in the conductive layer, or in the core material and the conductive layer have. In addition, the metal element most contained in the core material and the metal element most contained in the conductive layer may be alloyed with other metals. In addition, the metal contained in the core material and the metal contained in the conductive layer may be alloyed at the interface.

It is preferable that the metal element contained most in the core material and the metal element contained most in the first conductive layer are the same. In this case, the adhesion between the core material and the conductive layer becomes good, and as a result, the connection resistance in the connection structure is further improved. It is preferable that a metal element contained most in the core material and a metal element contained most in the first conductive layer are formed in the core material in the first conductive layer or between the core material and the first conductive layer , There may be a concentration gradient. The metal element contained most in the first conductive layer may be alloyed with another metal. The metal included in the core material and the metal included in the first conductive layer may be alloyed at the interface.

It is preferable that the metal element contained most in the core material and the metal element contained most in the second conductive layer are the same. In this case, the adhesion between the core material and the conductive layer becomes good, and as a result, the connection resistance in the connection structure is further improved. The metal element contained in the core material most frequently and the metal element most contained in the second conductive layer may be included in the core material in the second conductive layer or between the core material and the second conductive layer , There may be a concentration gradient. The metal element included in the second conductive layer may be alloyed with another metal. The metal included in the core material and the metal included in the second conductive layer may be alloyed at the interface.

Wherein the Mohs hardness of the core material is equal to the Mohs hardness of the portion of the conductive layer disposed between the base particles and the core material or the Mohs hardness of the core material is less than the Mohs hardness of the core Is preferably larger than the Mohs hardness of the layer portion. The Mohs hardness of the core material may be equal to the Mohs hardness of the first conductive layer, or the Mohs hardness of the core material may be greater than the Mohs hardness of the first conductive layer. In these cases, the core material is difficult to press-fit the base particles, and a part of the core material is difficult to sink into the base particles. As a result, the connection resistance between the electrodes can be further reduced. From the viewpoint of further lowering the connection resistance between the electrodes, the Mohs hardness of the core material is preferably larger than the Mohs hardness of the conductive layer portion disposed between the base particles and the core material or the first conductive layer.

From the viewpoint of further lowering the connection resistance when the Moh hardness of the core material is equal to or higher than the Moh hardness of the conductive layer portion disposed between the base material particles and the core material or the first conductive layer, The absolute value of the difference between the Mohs hardness of the first conductive layer and the Moh hardness of the conductive layer portion disposed between the base particles and the core material or the first conductive layer is preferably 0.1 or more and more preferably 0.5 or more.

The Mohs hardness of the core material is preferably smaller than the Mohs hardness of the conductive layer portion disposed between the base material particles and the core material. The Mohs hardness of the core material is preferably smaller than the Mohs hardness of the first conductive layer. In these cases, the conductive layer portion and the first conductive layer have a degree of cushioning. Thereby, it is not possible to lower the connection resistance by the conductive layer portion or the first conductive layer disposed between the base particles and the core material, and even if an impact is given to the connection structure in which the electrodes are connected by the conductive particles So that conduction failure is less likely to occur. That is, the impact resistance of the connection structure can be increased.

When the Mohs hardness of the core material is smaller than the Mohs hardness of the conductive layer portion disposed between the base particles and the core material or the first conductive layer, the Mohs hardness And the Mo hardness of the conductive layer portion disposed between the base particles and the core material or the first conductive layer is preferably 0.1 or more, and more preferably 0.5 or more.

[Substrate Particle]

Examples of the base particles include resin particles, inorganic particles other than metals, organic-inorganic hybrid particles and metal particles. The base particles are preferably base particles excluding metal particles, more preferably resin particles, inorganic particles other than metal, or organic-inorganic hybrid particles.

The base particles are preferably resin particles formed by a resin. If the base particles are resin particles, the effect of reducing the connection resistance obtained by the constitution of the conductive layer and the core material of the present invention becomes considerably large. When the electrodes are connected using the conductive particles, the conductive particles are disposed between the electrodes and then compressed to compress the conductive particles. When the base particles are resin particles, the conductive particles are liable to be deformed at the time of pressing, and the contact area between the conductive particles and the electrode is increased. Therefore, the conduction reliability between the electrodes is improved.

As the resin for forming the resin particles, various organic materials are preferably used. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyisobutylene, and polybutadiene; Acrylic resins such as polymethyl methacrylate and polymethyl acrylate; But are not limited to, polyalkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, melamine formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, A variety of polymerizable monomers having an epoxy resin, an unsaturated polyester resin, a saturated polyester resin, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, polyetheretherketone, polyether sulfone, , And polymers obtained by polymerizing two or more of them. It is possible to design and synthesize resin particles having physical properties at the time of compression appropriate for the conductive material and to control the hardness of the base particles to a desired range with ease. Therefore, the resin for forming the resin particles is preferably an ethylenically unsaturated Is preferably a polymer obtained by polymerizing one or more polymerizable monomers having a plurality of groups.

When the resin particles are obtained by polymerizing a monomer having an ethylenic unsaturated group, examples of the monomer having an ethylenic unsaturated group include a monomer which is incompatible with the monomer and a monomer which is crosslinkable.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and? -Methylstyrene; Carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; (Meth) acrylate, ethyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl Alkyl (meth) acrylates such as acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; (Meth) acrylates such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate; Nitrile-containing monomers such as (meth) acrylonitrile; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and propyl vinyl ether; Acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate and vinyl stearate; Unsaturated hydrocarbons such as ethylene, propylene, isoprene and butadiene; Halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride and chlorostyrene.

Examples of the crosslinkable monomer include tetramethylolmethane tetra (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane di (meth) acrylate, trimethylolpropane tri (meth) (Meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di Polyfunctional (meth) acrylates such as (poly) propylene glycol di (meth) acrylate, (poly) tetramethylene di (meth) acrylate and 1,4-butanediol di (meth) acrylate; (Meth) acryloxypropyltrimethoxysilane, trimethoxysilylstyrene, trimethylolpropane trimethoxysilane, triallyl trimellitate, divinyl benzene, diallyl phthalate, diallyl acrylamide, diallyl ether, , Silane-containing monomers such as vinyltrimethoxysilane, and the like.

The above-mentioned resin particles can be obtained by polymerizing the above-mentioned polymerizable monomer having an ethylenic unsaturated group by a known method. This method includes, for example, suspension polymerization in the presence of a radical polymerization initiator, and polymerization in which monomer is swollen together with radical polymerization initiator using non-crosslinked seed particles.

When the base particles are inorganic particles other than metal particles or organic-inorganic hybrid particles, examples of inorganic substances for forming the base particles include silica and carbon black. The particles formed by the silica are not particularly limited. For example, particles obtained by hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form cross-linked polymer particles, followed by baking if necessary, . Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed by a crosslinked alkoxysilyl polymer and an acrylic resin.

When the base particles are metal particles, examples of the metal for forming the metal particles include silver, copper, nickel, silicon, gold and titanium. However, it is preferable that the base particles are not metal particles.

The particle diameter of the base particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, still more preferably 1.5 μm or more, particularly preferably 2 μm or more, More preferably not more than 500 mu m, still more preferably not more than 300 mu m, further preferably not more than 50 mu m, further preferably not more than 30 mu m, particularly preferably not more than 5 mu m, 3 탆 or less. When the particle size of the base particles is not lower than the lower limit described above, the contact area between the conductive particles and the electrode becomes larger, so that the reliability of the conduction between the electrodes becomes further higher and the connection resistance between the electrodes connected via the conductive particles becomes further lower. Further, when the conductive layer is formed on the surface of the base particles by electroless plating, it is difficult to coagulate and the coagulated conductive particles are hardly formed. When the particle diameter is less than the upper limit, the conductive particles are easily compressed sufficiently, the connection resistance between the electrodes is further lowered, and the interval between the electrodes becomes smaller. The particle size of the base particles indicates a diameter when base particles are spherical, and indicates a maximum diameter when base particles are not spherical.

Particularly preferably, the particle size of the base particles is 0.1 占 퐉 or more and 5 占 퐉 or less. If the particle size of the base particles is within the range of 0.1 to 5 占 퐉, the interval between the electrodes becomes small, and even if the thickness of the conductive layer is made thick, small conductive particles can be obtained. The particle size of the base particles is preferably not less than 0.5 占 퐉, more preferably not less than 2 占 퐉, more preferably not less than 2 占 퐉, even more preferably not less than 2 占 퐉, more preferably not less than 2 占 퐉, Preferably 3 mu m or less.

[Conductive layer]

The metal for forming the conductive layer is not particularly limited. In the case where the conductive particles are metal particles whose entire surface is a conductive layer, the metal for forming the metal particles is not particularly limited. Examples of the metal include gold, silver, copper, palladium, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, , Molybdenum, alloys thereof, and the like. Examples of the metal include indium tin oxide (ITO) and solder. Among them, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is more preferable because the connection resistance between the electrodes can be further reduced. It is preferable that the metal element constituting the conductive layer includes nickel. The conductive layer preferably includes at least one selected from the group consisting of nickel, tungsten, molybdenum, palladium, phosphorus, and boron, and more preferably includes nickel, phosphorus, or boron. The material constituting the conductive layer may be an alloy including phosphorus and boron. In the conductive layer, nickel, tungsten or molybdenum may be alloyed.

When the conductive layer contains phosphorus or boron, the total content of phosphorus and boron in 100 wt% of the conductive layer is preferably 4 wt% or less. If the total content of phosphorus and boron is not more than the upper limit, the content of metal such as nickel becomes relatively large, so that the connection resistance between the electrodes is further lowered. The total content of phosphorus and boron in 100 wt% of the conductive layer is preferably 0.1 wt% or more, and more preferably 0.5 wt% or more.

Preferably, the metal element contained most in the core material, the conductive layer, and the second conductive layer is an alloy containing tin, nickel, palladium, copper, or gold, and more preferably nickel or palladium.

Like the conductive particles 1, the conductive layer may be formed by one layer. Further, like the conductive particles 11 and 21, the conductive layer may be formed of a plurality of layers. That is, the conductive layer may be a single layer or may have a laminated structure of two or more layers. When the conductive layer is formed of a plurality of layers, it is preferable that the outermost layer is a gold layer, a nickel layer, a palladium layer, a copper layer, or an alloy layer containing tin and silver, more preferably a gold layer or a palladium layer , And gold layer are particularly preferable. When the outermost layer is the preferable conductive layer, the connection resistance between the electrodes is further lowered. Further, when the outermost layer is a gold layer, corrosion resistance is further increased.

The method of forming the conductive layer on the surface of the base particles is not particularly limited. Examples of the method of forming the conductive layer include a method of electroless plating, a method of electroplating, a method of physical vapor deposition, and a method of coating a surface of base particles with a paste containing metal powder or metal powder and a binder And the like. Among them, the electroless plating method is preferable because the formation of the conductive layer is simple. Examples of the physical deposition method include vacuum deposition, ion plating and ion sputtering.

The average particle diameter of the conductive particles is preferably 0.11 m or more, more preferably 0.5 m or more, still more preferably 0.51 m or more, particularly preferably 1 m or more, preferably 100 m or less, 20 mu m or less, more preferably 5.6 mu m or less, particularly preferably 3.6 mu m or less. When the average particle diameter of the conductive particles is not less than the lower limit and not more than the upper limit, the contact area between the conductive particles and the electrode becomes sufficiently large when the electrodes are connected using the conductive particles, and when the conductive particles are aggregated, . Further, the distance between the electrodes connected via the conductive particles is not excessively large, and the conductive layer becomes difficult to peel off from the surface of the base particles.

The " average particle diameter " of the conductive particles indicates the number average particle diameter. The average particle diameter of the conductive particles is obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

The thickness of the conductive layer is preferably 0.005 m or more, more preferably 0.01 m or more, preferably 1 m or less, and more preferably 0.3 m or less. When the thickness of the conductive layer is not less than the lower limit and not more than the upper limit, sufficient conductivity is obtained, the conductive particles are not hardened too much, and the conductive particles are sufficiently deformed upon connection between the electrodes.

In the case where the conductive layer is formed of a plurality of layers, the thickness of the conductive layer in the outermost layer is preferably 0.001 m or more, more preferably 0.01 m or more, and preferably 0.5 m or less, 0.1 탆 or less. If the thickness of the conductive layer in the outermost layer is not less than the lower limit and not more than the upper limit, the covering by the conductive layer in the outermost layer can be made uniform, the corrosion resistance can be sufficiently increased, and the connection resistance between the electrodes .

The thickness of the conductive layer can be measured, for example, by observing the cross section of the conductive particles or the conductive particles having the insulating particles attached thereto using a transmission electron microscope (TEM).

The protrusions on the outer surface of the conductive layer per one conductive particle are preferably three or more, more preferably five or more. The upper limit of the number of the projections is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the average particle diameter of the conductive particles and the like.

[Core material]

Since the core material is embedded in the conductive layer, the conductive layer has a plurality of projections on the outer surface.

Examples of the method of forming the projections include a method in which a first conductive layer is formed on the surface of base particles, a core material is disposed on the first conductive layer, and then a second conductive layer is formed; And a method in which the core material is added during the step of forming the conductive layer on the surface.

Examples of the material constituting the core material include a conductive material and a non-conductive material. Examples of the conductive material include metals, oxides of metals, conductive nonmetals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene. Examples of the non-conductive material include silica, alumina, barium titanate, and zirconia. Among them, a metal is preferable because the conductivity can be increased and the connection resistance can be further effectively lowered. The core material is preferably a metal particle.

Examples of the metal include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, Alloys, tin-copper alloys, tin-silver alloys, tin-lead-silver alloys, and alloys composed of two or more metals such as tungsten carbide. Among them, nickel, copper, silver or gold is preferable. The metal constituting the core material may be the same as or different from the metal constituting the conductive layer. The metal constituting the core material preferably includes a metal constituting the conductive layer. The metal constituting the core material preferably includes nickel. The metal constituting the core material preferably includes nickel.

The shape of the core material is not particularly limited. The shape of the core material is preferably agglomerated. Examples of the core material include a lump of particles, an agglomerated mass agglomerated by a plurality of minute particles, and a lump of an irregular shape.

The average diameter (average particle diameter) of the core material is preferably 0.001 占 퐉 or more, more preferably 0.05 占 퐉 or more, preferably 0.9 占 퐉 or less, and more preferably 0.2 占 퐉 or less. When the average diameter of the core material is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The " average diameter (average particle diameter) " of the core material represents a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 pieces of any core material with an electron microscope or an optical microscope and calculating an average value.

The inorganic particles may be disposed on the surface of the core material. It is preferable that the number of the inorganic particles disposed on the surface of the core material is plural. An inorganic particle may be attached to the surface of the core material. Composite particles having such an inorganic particle and a core material may be used. The size (average diameter) of the inorganic particles is preferably smaller than the size (average diameter) of the core material, and the inorganic particles are preferably inorganic fine particles.

(Mohs hardness of 4.5), silica (silicon dioxide, Mohs hardness of 6 to 7), zirconia (Mohs hardness of 8 to 9), alumina (Mohs hardness of 9) as the material of the inorganic particles disposed on the surface of the core material, , Tungsten carbide (Mohs hardness 9), and diamond (Mohs hardness 10). The inorganic particles are preferably silica, zirconia, alumina, tungsten carbide or diamond, and silica, zirconia, alumina or diamond is also preferable. The Mohs hardness of the inorganic particles is preferably 5 or more, and more preferably 6 or more. The Mohs hardness of the inorganic particles is preferably larger than the Mohs hardness of the conductive layer. The Mohs hardness of the inorganic particles is preferably larger than the Mohs hardness of the second conductive layer. The absolute value of the difference between the Mohs hardness of the inorganic particles and the Mohs hardness of the conductive layer and the difference between the Mohs hardness of the inorganic particles and the Mohs hardness of the second conductive layer is preferably 0.1 or more, 0.2 or more, more preferably 0.5 or more, particularly preferably 1 or more. When the conductive layer is formed of a plurality of layers, the effect of reducing the connection resistance is more effectively exhibited when the inorganic particles are harder than all the metals constituting the plurality of layers.

The average particle diameter of the inorganic particles is preferably 0.0001 占 퐉 or more, more preferably 0.005 占 퐉 or more, preferably 0.5 占 퐉 or less, and more preferably 0.1 占 퐉 or less. When the average particle diameter of the inorganic particles is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The " average particle diameter " of the inorganic particles indicates the number average particle diameter. The average particle diameter of the inorganic particles is obtained by observing 50 arbitrary inorganic particles with an electron microscope or an optical microscope and calculating an average value.

In the case of using the composite particles in which the inorganic particles are disposed on the surface of the core material, the average diameter (average particle diameter) of the composite particles is preferably 0.0012 占 퐉 or more, more preferably 0.0502 占 퐉 or more, Mu m or less, and more preferably 1.2 mu m or less. When the average diameter of the composite particles is not less than the lower limit and not more than the upper limit, the connection resistance between the electrodes can be effectively lowered.

The " mean diameter (average particle diameter) " of the composite particles represents the number average diameter (number average particle diameter). The average diameter of the composite particles is determined by observing 50 arbitrary composite particles with an electron microscope or an optical microscope and calculating an average value.

[Insulating material]

The conductive particles according to the present invention preferably include an insulating material disposed on the surface of the conductive layer. In this case, if the conductive particles are used for connection between the electrodes, a short circuit between the adjacent electrodes can be prevented. Specifically, when a plurality of conductive particles are brought into contact with each other, an insulating material exists between a plurality of electrodes, so that a short circuit between electrodes adjacent to each other in the lateral direction, not between the upper and lower electrodes, can be prevented. Further, at the time of connection between the electrodes, the conductive particles of the conductive particles can be easily excluded from the insulating material between the electrodes by pressing the conductive particles with the two electrodes. Since the conductive particles have a plurality of protrusions on the outer surface of the conductive layer, the insulating material between the conductive layer of the conductive particles and the electrode can be easily removed.

It is preferable that the insulating material is an insulating particle since the insulating material can be more easily removed at the time of pressing between the electrodes.

Specific examples of the insulating resin as a material of the insulating material include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, crosslinked products of thermoplastic resins, thermoplastic resins, thermosetting resins and water- have.

Examples of the polyolefins include polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. Examples of the (meth) acrylate polymer include polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate. Examples of the block polymer include polystyrene, styrene-acrylic acid ester copolymer, SB-type styrene-butadiene block copolymer, SBS-type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include an epoxy resin, a phenol resin, and a melamine resin. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, methylcellulose and the like. Among them, a water-soluble resin is preferable, and polyvinyl alcohol is more preferable.

Methods for disposing the insulating material on the surface of the conductive layer include a chemical method and a physical or mechanical method. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, and an emulsion polymerization method. Examples of the physical or mechanical method include spray drying, hybridization, electrostatic deposition, spraying, dipping and vacuum deposition. Among them, a method of arranging the insulating material on the surface of the conductive layer through chemical bonding is preferable in that the insulating material is difficult to desorb.

The average diameter (average particle diameter) of the insulating material can be appropriately selected depending on the particle diameter of the conductive particles and the use of the conductive particles. The average diameter (average particle diameter) of the insulating material is preferably 0.005 占 퐉 or more, more preferably 0.01 占 퐉 or more, preferably 1 占 퐉 or less, and more preferably 0.5 占 퐉 or less. When the average diameter of the insulating material is not less than the lower limit described above, the conductive layers in the plurality of conductive particles are less likely to contact each other when the conductive particles are dispersed in the binder resin. When the average diameter of the insulating particles is less than the upper limit, it is not necessary to excessively increase the pressure in order to exclude the insulating material between the electrodes and the conductive particles at the time of connection between the electrodes, and it is unnecessary to heat the electrodes at a high temperature.

The " average diameter (average particle diameter) " of the insulating material indicates a number average diameter (number average particle diameter). The average diameter of the insulating material is obtained by using a particle size distribution measuring device or the like.

(Conductive material)

The conductive material according to the present invention includes the above-described conductive particles and a binder resin. The conductive particles are preferably dispersed in the binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material.

The binder resin is not particularly limited. As the binder resin, a known insulating resin is used.

Examples of the binder resin include a vinyl resin, a thermoplastic resin, a curable resin, a thermoplastic block copolymer and an elastomer. The binder resin may be used alone or in combination of two or more.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin and styrene resin. Examples of the thermoplastic resin include a polyolefin resin, an ethylene-vinyl acetate copolymer, and a polyamide resin. Examples of the curable resin include an epoxy resin, a urethane resin, a polyimide resin and an unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photo-curable resin or a moisture-curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymer include styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, hydrogenation product of styrene-butadiene-styrene block copolymer, and styrene-isoprene- Hydrogenated products, and the like. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

The conductive material may contain, in addition to the conductive particles and the binder resin, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, And the like.

As the method of dispersing the conductive particles in the binder resin, conventionally known dispersion methods can be used and there is no particular limitation. Examples of the method for dispersing the conductive particles in the binder resin include a method in which the conductive particles are added to the binder resin and then kneaded and dispersed with a planetary mixer or the like; a method in which the conductive particles are homogeneously dispersed in water or an organic solvent A method in which the binder resin is uniformly dispersed in a binder resin and then added to the binder resin and kneaded and dispersed by a planetary mixer or the like; and a method in which the binder resin is diluted with water or an organic solvent, Followed by kneading with a planetary mixer or the like and dispersing the mixture.

The conductive material according to the present invention can be used as a conductive paste and a conductive film. When the conductive material according to the present invention is a conductive film, a film not containing conductive particles may be laminated on the conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

The content of the binder resin in 100 wt% of the conductive material is preferably 10 wt% or more, more preferably 30 wt% or more, still more preferably 50 wt% or more, particularly preferably 70 wt% Is 99.99% by weight or less, and more preferably 99.9% by weight or less. When the content of the binder resin is not less than the lower limit and not more than the upper limit, the conductive particles are efficiently disposed between the electrodes, and the connection reliability of the connection target member connected by the conductive material is further enhanced.

The content of the conductive particles in 100 wt% of the conductive material is preferably 0.01 wt% or more, more preferably 0.1 wt% or more, preferably 40 wt% or less, more preferably 20 wt% or less, Is not more than 10% by weight. When the content of the conductive particles is not less than the lower limit and not more than the upper limit, the reliability of the conduction between the electrodes is further increased.

(Connection structure)

The connection structure can be obtained by connecting the members to be connected using the conductive particles of the present invention or by using the conductive particles and the conductive material containing the binder resin.

Wherein the connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, wherein the connection portion is formed by the conductive particles of the present invention, or And is preferably a connection structure formed by a conductive material (anisotropic conductive material or the like) including the conductive particles and a binder resin. In the case where conductive particles are used, the connection itself is a conductive particle. That is, the first and second connection target members are connected by the conductive particles.

4 is a front sectional view schematically showing a connection structure using conductive particles according to a first embodiment of the present invention.

The connection structure 51 shown in Fig. 4 includes a connection member 54 connecting the first connection object member 52, the second connection object member 53 and the first and second connection object members 52 and 53 . The connecting portion 54 is formed by curing a conductive material containing the conductive particles 1. [ In Fig. 4, the conductive particles 1 are schematically shown for convenience of illustration.

The first connection target member 52 has a plurality of electrodes 52b on its upper surface 52a (surface). The second connection target member 53 has a plurality of electrodes 53b on the lower surface 53a (surface). And the electrode 52b and the electrode 53b are electrically connected to each other by one or a plurality of conductive particles 1. [ Therefore, the first and second connection target members 52 and 53 are electrically connected by the conductive particles 1. [

The manufacturing method of the connection structure is not particularly limited. As an example of a manufacturing method of the connection structure, there is a method of arranging the conductive material between the first connection target member and the second connection target member to obtain a laminate, and then heating and pressing the laminate.

The pressure of the pressurization is about 9.8 x 10 ⁴ to 4.9 x 10 ⁶ Pa. The temperature of the heating is about 120 to 220 占 폚.

Specifically, examples of the member to be connected include electronic parts such as semiconductor chips, condensers and diodes, and electronic parts such as printed boards, flexible printed boards and circuit boards such as glass boards. The connection target member is preferably an electronic component. The conductive particles are preferably used for electrical connection of electrodes in an electronic component.

Examples of the electrode provided on the member to be connected include metal electrodes such as a gold electrode, a nickel electrode, a tin electrode, an aluminum electrode, a copper electrode, a molybdenum electrode, and a tungsten electrode. When the connection target member is a flexible printed board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, or a copper electrode. When the connection target member is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of the metal oxide layer. Examples of the material of the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal element include Sn, Al and Ga.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)

(1) palladium deposition process

And a divinylbenzene resin particle (Micropearl SP-205, manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 5.0 mu m was prepared. The resin particles were etched and washed with water. Next, resin particles were added to 100 mL of a palladium catalyzed solution containing 8 wt% of palladium catalyst and stirred. Thereafter, it was filtered and washed. Resin particles were added to a 0.5 wt% dimethylamine borane solution having a pH of 6 to obtain resin particles having palladium attached thereto.

(2) Electroless nickel plating process

A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite, 0.15 mol / L of sodium citrate and 0.01 mol / L of sodium molybdate was added to form a nickel- Prepared.

Palladium-adhered resin particles obtained in 1000 mL of pure water were added and dispersed with an ultrasonic disperser to obtain a suspension. While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain resin particles coated with a nickel-phosphorus layer (nickel-molybdenum-phosphorus layer (Ni-Mo-P layer) To obtain particles having the first conductive layer formed thereon.

(3) Core material deposition process and electroless nickel plating process

Alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was prepared. The first conductive layer was formed and the metal particle slurry was used to coat the first conductive layer.

A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite, 0.15 mol / L of sodium citrate and 0.01 mol / L of sodium molybdate was added to form a nickel- Prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was gradually dropped into the suspension and electroless nickel plating was performed to form a second conductive layer (nickel-molybdenum-phosphorus layer (Ni-Mo-P layer) The conductive particles thus obtained had protrusions on the outer surface of the second conductive layer and were formed on the inner side of the protrusions of the second conductive layer, and the particles were removed by filtration, washed with water, and dried to obtain conductive particles. And the core material was disposed. Also, the first conductive layer was disposed between the resin particle and the core material.

(Example 2)

Conductive particles were obtained in the same manner as in Example 1 except that alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was changed to silica particle slurry (average particle diameter 100 nm).

(Example 3)

Conductive particles were obtained in the same manner as in Example 1 except that alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was changed to tungsten carbide (WC) particle slurry (average particle diameter 100 nm).

(Examples 4 to 8)

Conductive particles were obtained in the same manner as in Example 1 except that the thickness of the first conductive layer as the nickel-phosphorous layer was changed to the following values.

Thickness of the first conductive layer:

Example 4: 10 占 퐉

Example 5: 20 占 퐉

Example 6: 100 占 퐉

Example 7: 750 占 퐉

Example 8: 860 mu m

(Example 9)

(1) Preparation of insulating particles

100 mmol of methyl methacrylate and 100 mmol of N, N, N-trimethyl-N-2-methacryloxypropyltrimethoxysilane were added to a 1000-mL separable flask equipped with a four-necked separable cover, stirrer, three-way cock, A monomer composition comprising 1 mmol of roile oxyethylammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride was weighed into ion-exchange water so that the solids content would be 5% by weight ), The mixture was stirred at 200 rpm, and polymerization was carried out at 70 캜 for 24 hours in a nitrogen atmosphere. After completion of the reaction, the resultant was lyophilized to obtain insulating particles having an ammonium group on the surface and an average particle diameter of 220 nm and a CV value of 10%.

The insulating particles were dispersed in ion-exchanged water under ultrasonic irradiation to obtain a 10 wt% aqueous dispersion of insulating particles.

10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. The mixture was filtered with a 3 탆 mesh filter, then washed with methanol, and dried to obtain conductive particles having insulating particles adhered thereto.

As a result of observation by a scanning electron microscope (SEM), only one coating layer composed of insulating particles was formed on the surface of the conductive particles. The coated area of the insulating particles (i.e., the projected area of the particle diameter of the insulating particles) from the center of the conductive particles to the area of 2.5 占 퐉 was calculated by image analysis, and the coating rate was 30%.

(Example 10)

Divinylbenzene resin particles (Micropearl SP-205, manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 5.0 占 퐉 were dispersed in 100 parts by mass of a microparticulate dispersion of 5.0 占 퐉 in size of divinylbenzene resin particles (Micropearl SP manufactured by Sekisui Chemical Co., Quot; -205 ") was changed to organic-inorganic hybrid particles (particle size: 5.1 mu m) in which the surface of the inorganic particles was coated with silica to obtain conductive particles.

(Comparative Example 1)

Conductive particles were obtained in the same manner as in Example 1 except that the thickness of the first conductive layer as the nickel-phosphorous layer was changed to 4.5 nm.

(Comparative Example 2)

And a divinylbenzene resin particle (Micropearl SP-205, manufactured by Sekisui Chemical Co., Ltd.) having a particle diameter of 5.0 탆 was prepared. Further, an alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was prepared. Using the resin particles and the metal particle slurry, the surface of the resin particles was covered with a core material to obtain a suspension.

A nickel plating solution (pH 8.0) containing 0.25 mol / L of nickel sulfate, 0.25 mol / L of sodium hypophosphite, 0.15 mol / L of sodium citrate and 0.01 mol / L of sodium molybdate was added to form a nickel- Prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out to form a conductive layer having a thickness of 100 nm. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain conductive particles. In the obtained conductive particles, the core material and base particles were in contact with each other.

(Example 11)

(1) palladium deposition process

The palladium-adhered resin particles obtained in Example 1 were prepared.

(2) Electroless nickel plating process

A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

Palladium-adhered resin particles obtained in 1000 mL of pure water were added and dispersed with an ultrasonic disperser to obtain a suspension. While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain particles having the first conductive layer formed by coating the resin particles with a first conductive layer (thickness: 5.1 nm) which is a nickel-tungsten-boron layer.

(3) Core material deposition process and electroless nickel plating process

Alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was prepared. The first conductive layer was formed and the metal particle slurry was used to coat the first conductive layer.

A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was gradually dropped into the suspension, and electroless nickel plating was carried out to form a second conductive layer with a thickness of 90 nm. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain conductive particles. The obtained conductive particles had protrusions on the outer surface of the second conductive layer, and the core material was disposed inside the protrusions of the second conductive layer. Further, the first conductive layer was disposed between the resin particles and the core material.

(Example 12)

Conductive particles were obtained in the same manner as in Example 11 except that the thickness of the first conductive layer which was a nickel-tungsten-boron layer was changed to 10 nm.

(Example 13)

Conductive particles were obtained in the same manner as in Example 11 except that the thickness of the first conductive layer which was a nickel-tungsten-boron layer was changed to 20 nm.

(Example 14)

10% by weight aqueous dispersion of the insulating particles obtained in Example 9 was prepared. 10 g of the conductive particles obtained in Example 11 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. The mixture was filtered with a 3 탆 mesh filter, then washed with methanol, and dried to obtain conductive particles having insulating particles adhered thereto.

As a result of observation by a scanning electron microscope (SEM), only one coating layer composed of insulating particles was formed on the surface of the conductive particles. The coated area of the insulating particles (i.e., the projected area of the particle diameter of the insulating particles) from the center of the conductive particles to the area of 2.5 占 퐉 was calculated by image analysis, and the coating rate was 30%.

(Comparative Example 3)

Conductive particles were obtained in the same manner as in Example 11 except that the thickness of the first conductive layer, which was a nickel-tungsten-boron layer, was changed to 3 nm.

(Comparative Example 4)

And a divinylbenzene resin particle (Micropearl SP-205, manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 5.0 mu m was prepared. Further, an alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm) was prepared. Using the resin particles and the metal particle slurry, the surface of the resin particles was covered with a core material to obtain a suspension.

A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out to form a conductive layer having a thickness of 100 nm. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain conductive particles. In the obtained conductive particles, the core material and base particles were in contact with each other.

(Example 15)

(1) palladium deposition process

The palladium-adhered resin particles obtained in Example 1 were prepared.

(2) Electroless nickel plating process

A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

Palladium-adhered resin particles obtained in 1000 mL of pure water were added and dispersed with an ultrasonic disperser to obtain a suspension. While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain particles having the first conductive layer formed by covering the resin particles with a first conductive layer having a thickness of 10 nm, which is a nickel-tungsten-boron layer.

(3) Core material deposition process and electroless nickel plating process

A barium titanate (BaTiO ₃ ) particle slurry (average particle diameter 100 nm) was prepared. The surface of the first conductive layer was covered with metal particles by using the particles having the first conductive layer and the metal particle slurry to obtain a suspension.

A nickel plating solution (pH 7.0) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane and 0.5 mol / L of sodium citrate was prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was gradually dropped into the suspension, and electroless nickel plating was carried out to form a second conductive layer with a thickness of 90 nm. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain conductive particles. The obtained conductive particles had protrusions on the outer surface of the second conductive layer, and the core material was disposed inside the protrusions of the second conductive layer. Further, the first conductive layer was disposed between the resin particles and the core material.

(Example 16)

Conductive particles were obtained in the same manner as in Example 15 except that the thickness of the first conductive layer which was a nickel-tungsten-boron layer was changed to 5.1 nm.

(Example 17)

Conductive particles were obtained in the same manner as in Example 15 except that the thickness of the first conductive layer which was a nickel-tungsten-boron layer was changed to 20 nm.

(Example 18)

Conductive particles were obtained in the same manner as in Example 15 except that the slurry of barium titanate (BaTiO ₃ ) (average particle diameter 100 nm) was changed to alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm).

(Example 19)

Conductive particles were obtained in the same manner as in Example 16 except that a slurry of barium titanate (BaTiO ₃ ) (average particle diameter 100 nm) was changed to an alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm).

(Example 20)

Conductive particles were obtained in the same manner as in Example 17 except that the slurry of barium titanate (BaTiO ₃ ) (average particle diameter 100 nm) was changed to alumina (Al ₂ O ₃ ) particle slurry (average particle diameter 100 nm).

(Example 21)

Conductive particles were obtained in the same manner as in Example 15 except that 0.01 mol / L of sodium tungstate was added to the nickel plating solution for forming the second conductive layer.

(Example 22)

10% by weight aqueous dispersion of the insulating particles obtained in Example 9 was prepared. 10 g of the conductive particles obtained in Example 15 was dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. The mixture was filtered with a 3 탆 mesh filter, then washed with methanol, and dried to obtain conductive particles having insulating particles adhered thereto.

As a result of observation by a scanning electron microscope (SEM), only one coating layer composed of insulating particles was formed on the surface of the conductive particles. The coated area of the insulating particles (i.e., the projected area of the particle diameter of the insulating particles) from the center of the conductive particles to the area of 2.5 占 퐉 was calculated by image analysis, and the coating rate was 30%.

(Comparative Example 5)

And a divinylbenzene resin particle (Micropearl SP-205, manufactured by Sekisui Chemical Co., Ltd.) having a particle size of 5.0 mu m was prepared. Further, a barium titanate (BaTiO ₃ ) particle slurry (average particle diameter 100 nm) was prepared. Using the resin particles and the metal particle slurry, the surface of the resin particles was covered with a core material to obtain a suspension.

A nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane, 0.5 mol / L of sodium citrate and 0.01 mol / L of sodium tungstate was prepared.

While stirring the obtained suspension at 60 占 폚, the nickel plating solution was slowly dropped into the suspension, and electroless nickel plating was carried out to form a conductive layer having a thickness of 100 nm. Thereafter, the suspension was filtered to take out the particles, washed with water and dried to obtain conductive particles. In the obtained conductive particles, the core material and base particles were in contact with each other.

(Comparative Example 6)

Conductive particles were obtained in the same manner as in Example 18 except that the thickness of the first conductive layer, which is a nickel-tungsten-boron layer, was changed to 1 nm.

(Example 23)

10% by weight aqueous dispersion of the insulating particles obtained in Example 9 was prepared. 10 g of the conductive particles obtained in Example 18 were dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. The mixture was filtered with a 3 탆 mesh filter, then washed with methanol, and dried to obtain conductive particles having insulating particles adhered thereto.

As a result of observation by a scanning electron microscope (SEM), only one coating layer composed of insulating particles was formed on the surface of the conductive particles. The coated area of the insulating particles (i.e., the projected area of the particle diameter of the insulating particles) from the center of the conductive particles to the area of 2.5 占 퐉 was calculated by image analysis, and the coating rate was 30%.

(evaluation)

(1) the average distance between the surface of the base particles and the surface of the core material

The obtained conductive particles were cut and observed by a section to measure the distance between the surface of the base particles and a plurality of core materials. The distance between the surface of the base particle and the surface of the core material was measured by photographing a plurality of cross sections of the conductive particle to obtain an image, creating a stereoscopic image from the obtained image, and using the obtained stereoscopic image. The section was photographed using a Helios NanoRab. 650 apparatus, which was manufactured by Nippon FEI Co., Ltd., and focused on a focused ion beam-scanning electron microscope (FIBSEM). A thin film segment of conductive particles was produced using a focused ion beam, and a cross section was observed with a scanning electron microscope. The operation was repeated 200 times and image analysis was performed to obtain a three-dimensional image of the particles. From the stereoscopic image, the distance between the surface of the base particle and the surface of the core material was determined.

(2) a ratio (%) of the number of core materials having a distance between the surface of the base particle and the surface of the core material exceeding 5 nm, out of 100%

(%) Of the number of core materials having a distance of 5 nm or more between the surface of the base material particle and the surface of the core material in the total number of 100% by weight of the core material , And was judged according to the following criteria.

[Criteria of the ratio (%) of the number of core materials having a distance between the surface of the base particles and the surface of the core material exceeding 5 nm]

A: If the ratio of the number exceeds 80%

B: the ratio of the number is 80% or less

(3) Connection resistance

Preparation of the connection structure:

10 parts by weight of a bisphenol A type epoxy resin ("Epikote 1009" manufactured by Mitsubishi Chemical Corporation), 40 parts by weight of an acrylic rubber (weight average molecular weight: about 800,000), 200 parts by weight of methyl ethyl ketone, , And 2 parts by weight of a silane coupling agent (" SH6040 ", manufactured by Toray Dow Corning Silicone Co., Ltd.) were mixed and dispersed to prepare a conductive particle having a content of 3 wt% To obtain a resin composition.

The obtained resin composition was applied to a PET (polyethylene terephthalate) film having a thickness of 50 占 퐉 on one side of which had been subjected to release treatment and dried for 5 minutes by hot air at 70 占 폚 to prepare an anisotropic conductive film. The thickness of the resulting anisotropic conductive film was 12 占 퐉.

The obtained anisotropic conductive film was cut into a size of 5 mm x 5 mm. The cut anisotropic conductive film was placed on one side of a glass substrate (3 cm wide, 3 cm long) having aluminum electrodes (height 0.2 μm, L / S = 20 μm / 20 μm) In the vicinity of the center. Subsequently, a two-layer flexible printed substrate (2 cm wide, 1 cm long) having the same aluminum electrode was positioned and aligned so that the electrodes overlapped with each other. The laminate of the glass substrate and the two-layer flexible printed substrate was subjected to thermocompression bonding under conditions of 10 N, 180 占 폚 and 20 seconds to obtain a connection structure. Further, a two-layer flexible printed substrate having an aluminum electrode directly formed on a polyimide film was used.

Measurement of connection resistance:

The connection resistance between the opposing electrodes of the resulting connection structure was measured by the four-terminal method. Further, the connection resistance was judged based on the following criteria.

[Criteria for judging connection resistance]

○○: Connection resistance is 2.0Ω or less

○: Connection resistance is more than 2.0Ω and less than 3.0Ω

?: Connection resistance is more than 3.0? 5.0?

×: Connection resistance exceeded 5.0Ω

(4) Impact resistance

The impact resistance was evaluated by dropping the connection structure obtained in the above (3) evaluation of connection resistance at a height of 70 cm and confirming continuity. From the rate of rise of the resistance value from the initial resistance value, the impact resistance was judged based on the following criteria.

[Criteria for determination of impact resistance]

○○: The increase rate of the resistance value from the initial resistance value is 20% or less

○: The increase rate of the resistance value from the initial resistance value is more than 20% and not more than 35%

?: Increase rate of the resistance value from the initial resistance value exceeds 35% to 50% or less

X: Increase rate of the resistance value from the initial resistance value exceeds 50%

(5) the state of indentation

(3) The electrode provided on the glass substrate was observed on the glass substrate side of the connection structure obtained in the above (3) evaluation of the connection resistance, and the presence or absence of the indentation of the electrode with which the conductive particles were contacted was judged by the following judgment criteria Respectively. With respect to the presence or absence of indentation of the electrode, the number of indentations per electrode area of 0.02 mm 2 was calculated by observation with a differential interference microscope so that the electrode area was 0.02 mm 2. 10 arbitrary points were observed with a differential interference microscope to calculate an average value of the number of indentations per 0.02 mm 2 of electrode area.

[Judgment Criteria of Indentation Condition]

?: The average value of the number of indentations per 0.02 mm2 electrode area is 20 or more

?: Average value of the number of indentations per 0.02 mm2 of the electrode area is 5 or more and less than 20

X: Average value of the number of indentations per 0.02 mm2 electrode area is less than 5

The results are shown in Tables 1 to 3 below. The Mohs hardness of the first and second conductive layers and the core material are shown in Tables 1 to 3 below. In the following Tables 1 to 3, " - " indicates that it is not evaluated.

One… Conductive particle
2… Base particles
3 ... Conductive layer
3a ... spin
3b ... Conductive layer portion
4… Core material
5 ... Insulating material
11 ... Conductive particle
12 ... Conductive layer
12a ... spin
12b ... Conductive layer portion
16 ... The first conductive layer
17 ... The second conductive layer
17a ... spin
21 ... Conductive particle
22 ... Conductive layer
22a ... spin
22b ... Conductive layer portion
26 ... The first conductive layer
27 ... The second conductive layer
27a ... spin
28 ... The third conductive layer
28a ... spin
51 ... Connection structure
52 ... The first connection object member
52a ... Top surface
52b ... electrode
53 ... The second connection object member
53a ... if
53b ... electrode
54 ... Connection

Claims (11)

Base particles,
A conductive layer covering the base particles;
Embedded in the conductive layer (

And a plurality of core materials,
Wherein the conductive layer has a plurality of projections on an outer surface thereof and the core material is disposed inside the projections of the conductive layer,
Wherein the conductive layer is disposed between the base particles and the core material and the surface of the base particles and the surface of the core material are spaced apart and the average distance between the surface of the base particles and the surface of the core material is The conductive particles exceeding 5 nm and not more than 20 nm. delete The method of claim 1, wherein a ratio of the number of core materials having a diameter of 20 nm or more to a surface of the core material is 5 nm or more and 100% or more of the total number of core materials is 100% % Or less. The conductive particle according to claim 1 or 3, wherein the metal element most contained in the core material and the metal element most contained in the conductive layer are the same. 4. The semiconductor device according to claim 1 or 3, wherein the conductive layer comprises a first conductive layer covering the base particles, and a second conductive layer covering the first conductive layer and the core material,
Wherein the core material is disposed on a surface of the first conductive layer and embedded in the second conductive layer,
Wherein the second conductive layer has a plurality of projections on an outer surface thereof,
Wherein the core material is disposed inside the projection of the second conductive layer,
And the first conductive layer is disposed between the base particles and the core material. 6. The conductive particle according to claim 5, wherein the metal element most contained in the core material and the metal element most contained in the second conductive layer are the same. The conductive particle according to claim 1 or 3, wherein the conductive layer is a single-layer conductive layer. The conductive particle according to claim 1 or 3, wherein the core material is metal particles. The conductive particle according to claim 1 or 3, further comprising an insulating material attached to a surface of the conductive layer. A conductive material comprising the conductive particles according to any one of claims 1 to 3 and a binder resin. A first connection object member,
A second member to be connected,
And a connection portion connecting the first and second connection target members,
Wherein the connecting portion is formed by the conductive particles according to claim 1 or 3, or is formed by a conductive material including the conductive particles and the binder resin.

Images